1. Field of the Invention
The present invention generally relates to a light guide plate and a backlight module; particularly, the present invention relates to a light guide plate and a backlight module with increased light guide efficiency.
2. Description of the Prior Art
In general, according to position of light source in a backlight module, backlight modules at least include edge type backlight modules and direct type backlight modules. For instance, the edge type backlight modules have advantages of slim, high light-generating efficiency, and are widely applied in display devices.
Please refer to FIG. 1; FIG. 1 is a side view of a conventional edge type backlight module. As shown in FIG. 1, the backlight module 12 includes a side light source 12A, a light guide plate 12B, and a wedge body 12C, wherein the side light source 12A is disposed on a side of the light guide plate 12B, and the wedge body 12C is connected adjacently with the side light source 12A and the light guide plate 12B. In addition, the wedge body has a wedge width W, the light guide plate 12 has a thickness T1, and thickness T2 is the biggest thickness of the wedge. Practically, the wedge body 12C assists to guide the light generated from the side light source 12A into the light guide plate 12B so as to increase inner guiding energy.
FIG. 2 is a curve diagram showing light guide efficiency of a conventional edge type backlight module. As shown in FIG. 2, the light guide efficiency of the backlight module 12 obviously gets worse when the thickness T1 of the light guide plate 12B is reducing, the thickness T2 is increasing, or the wedge width W is reducing. In addition, as light-guide-efficiency curve C4 in FIG. 2 shows, the thickness T2 is 0.6 mm, the wedge width W is 0.5 mm. For the purpose of thinner, as the thickness T1 of the light guide plate 12B is 0.2 mm, the light-guide-efficiency is 35%, it is unable to acquire better light-guide-efficiency. Take the light-guide-efficiency curve C3, after increasing the wedge width W from 0.5 mm to 2.0 mm, the best light-guide-efficiency of the light guide plate 12B with the thickness T1 0.2 mm is 45%, and the hot spot defective rate is 5%, it cannot achieve the efficacy of thinner and high light guide efficiency at the same time.